A genuine Thetford OEM green measuring cap designed for C400 series cassette toilets. This cap serves a dual purpose. sealing the waste-holding tank outlet and providing an accurate measuring cup for toilet additives. If your cap is cracked, leaking, or missing, this replacement restores a tight seal and makes it easy to measure chemicals correctly.

Part Number: 2581016

Colour: Green

Function: Waste tank cap and measuring cup

Material: High-strength ABS plastic

1 × Green waste tank measuring cap

Compatability:

• Designed specifically for Thetford C400 series cassette toilets (including C402, C403, and C404 models)

• Fits directly onto the waste-holding tank spout

Frequently Asked Questions

Q: What does this cap do?
It seals the waste tank’s spout and also functions as a measuring cup for accurately dosing toilet chemicals like Thetford Aqua Kem.

Q: How do I use it to measure additive?
Simply pour the correct amount of additive (as per product instructions) into the cap, then empty it into the tank before tightening the cap securely.

Q: Is this the waste tank cap or the flush water cap?
This is the waste tank cap.

Q: Can I use this on other Thetford models like the C250 or C260?
No ,  this green cap only fits the C400 waste tank.